arm64: percpu: Implement this_cpu operations

Browse source

The generic this_cpu operations disable interrupts to ensure that the
requested operation is protected from pre-emption. For arm64, this is
overkill and can hurt throughput and latency.

This patch provides arm64 specific implementations for the this_cpu
operations. Rather than disable interrupts, we use the exclusive
monitor or atomic operations as appropriate.

The following operations are implemented: add, add_return, and, or,
read, write, xchg. We also wire up a cmpxchg implementation from
cmpxchg.h.

Testing was performed using the percpu_test module and hackbench on a
Juno board running 3.18-rc4.

Signed-off-by: Steve Capper <steve.capper@linaro.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

...

This commit is contained in:

Steve Capper 2014-11-19 16:53:43 +00:00 • committed by Will Deacon

parent 15670ef1ea

commit f97fc81079

2 changed files with 219 additions and 2 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

6

arch/arm64/include/asm/cmpxchg.h

View file

215

arch/arm64/include/asm/percpu.h

View file